I used puppet (masterless) in a small company, and in my new company I'm using Ansible and Docker. Puppet and Chef are great, but they're overkill unless you have large infrastructure. If there's only one of you doing 'ops', you don't have large enough infra (in my opinion). Ansible is easy to configure and learn, and doesn't wrap you in dependency hell like puppet can.

I would avoid Docker until you have a use-case that Docker solves for you. Use your preferred distro's packaging technique. It can be a bit of a pain (.deb in particular) to start with, but once you're familiar, it's portable and manageable with your OS's native tools. Things 'just work', and don't need an agent to be installed and kept up-to-date. If something goes wrong, it's in your OS's standard logs, not some strange arcane location. And most importantly, you have a bigger pool of interneteers to help learn from and troubleshoot with. I can't complain about the Docker IRC channel, good experience there, but there's still fewer of them.

If you are a .debber and want your own repo, check out Aptly, which makes life much easier than previous repo software on offer. http://www.aptly.info/

TL;DR: Docker is 'another thing to learn', and it's not trivial. Put it off until it solves a problem for you; there's plenty of other stuff to get up to speed with.